1. Field of the Invention
The present invention relates to an audio signal processing and reproducing method for processing and reproducing an audio signal while adjusting a sound quality of a music reproduced by the audio signal, an audio signal processing apparatus for processing an audio signal with sound quality controlling information indicating various sound qualities of a music reproduced by the audio signal, a recording medium for recording an audio signal with sound quality controlling information indicating various sound qualities of a music reproduced by the audio signal, and an audio signal reproducing apparatus for reproducing an audio signal while adjusting a music reproduced by the audio signal to a desired sound quality.
Also, the present invention relates to an audio signal processing and reproducing method for processing and reproducing an audio signal while reducing a volume of data indicating the audio signal, an audio signal processing apparatus for processing an audio signal while reducing a volume of data indicating the audio signal, a recording medium for recording an audio signal in which a volume of data indicating the audio signal is reduced, and an audio signal reproducing apparatus for reproducing an audio signal processed to reduce a volume of data indicating the audio signal. Also, the present invention relates to an audio signal processing and reproducing method for processing and reproducing an audio signal while adjusting an output level of the audio signal, an audio signal processing apparatus for processing an audio signal with a test tone signal to automatically mute an output sound of the test tone signal in a reproducing operation of the audio signal, a recording medium for recording an audio signal with a test tone signal, and an audio signal reproducing apparatus for reproducing an audio signal with a test tone signal while adjusting an output level of the audio signal and muting an output sound of the test tone signal.
2. Description of the Related Art
2.1. First Previously Proposed Art
In general, in cases where an audio signal recorded in a recording medium such as a compact disk (or disc) (CD) or a digital versatile disk (or disc) (DVD) is reproduced by using a speaker, a user can entertain a music reproduced by the audio signal at a desired sound quality when the user manually operates an equalizer of an audio signal reproducing apparatus to appropriately adjust a level of each frequency band such as a low tone or a high tone, a balance of levels of frequency bands, a level balance of speakers of five channels (or right and left channels) and reverberation.
2.2. Second Previously Proposed Art
In a first conventional audio signal reproducing method, when a digital audio signal is written in a CD or DVD as an original signal, a level of the original signal is generally heightened to improve a sound/noise (S/N) ratio in the original signal. Also, in cases where a level of an original signal read out from the CD or DVD is too high, the level of the original signal is lowered in a reproducing operation to prevent the original signal from giving an unpleasant feeling to a listener or to prevent a speaker from being broken. In this case, a user can reproduce the original signal at a desired level by manually adjusting the level of the original signal in the reproducing operation.
Also, in a second conventional audio signal reproducing method, when a test tone recorded in a disk (or disc) at a maximum level for each channel of a stereo or multichannel is reproduced, an operator manually mutes an output sound including the test tone and manually adjusts the balance of levels of the test tones in a plurality of channels while observing the levels indicated in a level meter.
2.3. Problems to be Solved by the Invention
However, when the user entertains a music at a desired sound quality, the user is required to manually operate many buttons for appropriately adjusting a level of each frequency band, a balance of levels of frequency bands, a level balance of speakers of five channels and reverberation. Also, to appropriately adjust the buttons, a skillful person having a superior keen sense of hearing such as a professional mixer is required. Therefore, the user cannot hear a music at a desired sound quality.
Also, in the first conventional audio signal reproducing method, because a level of an original digital audio signal is shifted and the signal is recorded, the user is required to adjust the level of the signal when the user reproduces the signal at an original level thereof. Therefore, there is a drawback that the digital audio signal cannot be automatically reproduced at the original level.
Also, in the second conventional audio signal reproducing method, because it is required to record one test tone in each of all recording blocks of a disk (or disc), a recording area of the disk (or disc) cannot be efficiently used for digital recording signals. To prevent this drawback, there is an idea that each of test tones is recorded in an area of the disk (or disc) with a mute flag and an output of an audio signal for which one mute flag is set is muted. In this idea, the burden for watching the mute flags is increased in an audio signal reproducing apparatus when an occurrence frequency of the mute flags is heightened. For example, one mute flag is set for each frame (1/600 second). Also, when an occurrence frequency of the mute flag is lowered, a fine mute control for the audio signal cannot be performed.
A first object of the present invention is to provide, with due consideration to the drawbacks of such a conventional audio signal reproducing method, an audio signal processing and reproducing method in which an audio signal is reproduced at a simple operation on condition that a sound quality of a music indicated by the audio signal is appropriately set, an audio signal processing apparatus in which an audio signal is processed to be reproduced at a desired sound quality, a recording medium in which an audio signal processed by the audio signal processing apparatus is recorded, and an audio signal reproducing apparatus in which an audio signal processed by the audio signal processing apparatus is reproduced at a desired sound quality.
A second object of the present invention is to provide an audio signal processing and reproducing method in which an audio signal is processed at reduced data volume and is automatically reproduced at an original level, an audio signal processing apparatus in which an analog audio signal is processed while reducing a volume of data indicating the analog audio signal, a recording medium in which digital audio signal expressing an analog audio signal at a reduced data volume is recorded and an audio signal reproducing apparatus in which an analog audio signal expressed at a reduced data volume is reproduced.
A third object of the present invention is to provide an audio signal processing and reproducing method in which an audio signal is processed with a test tone signal and the audio signal is easily reproduced at an output level adjusted according to the test tone signal without giving an unpleasant feeling based on an output sound of the test tone signal to a user, an audio signal processing apparatus in which an audio signal is processed with a test tone signal to be reproduced without giving an unpleasant feeling based on an output sound of the test tone signal to a user, a recording medium in which an audio signal processed with a test tone signal is recorded and an audio signal reproducing apparatus in which an audio signal processed with a test tone signal is easily reproduced without giving an unpleasant feeling based on an output sound of the test tone signal to a user.
The first object is achieved by the provision of an audio signal processing and reproducing method, comprising the steps of:
converting an analog audio signal of a channel into a digital audio signal composed of a plurality of pieces of audio data;
adding a plurality of pieces of sound quality control information, which each denote information for adjusting a sound quality of a music indicated by the analog audio signal, to the digital audio signal;
recording a set of the digital audio signal and the pieces of sound quality control information;
reading out the set of the digital audio signal and the pieces of sound quality control information;
selecting a piece of particular sound quality control information from the pieces of sound quality control information;
adjusting levels of the pieces of audio data of the digital audio signal according to the particular sound quality control information to produce a sound quality adjusted digital audio signal composed of a plurality of pieces of sound quality adjusted audio data having adjusted levels; and
outputting the sound quality adjusted digital audio signal.
The first object is also achieved by the provision of an audio signal processing apparatus, comprising:
analog-digital converting means for converting an analog audio signal of a channel into a digital audio signal composed of a plurality of pieces of audio data; and
audio signal encoding means for adding a plurality of pieces of sound quality control information, which each denote information for adjusting a sound quality of a music indicated by the analog audio signal, to the digital audio signal and encoding the digital audio signal and the pieces of sound quality control information to produce packed data, the packed data being transmitted or recorded.
In the above steps and configuration, a plurality of pieces of sound quality control information are added to a digital audio signal obtained from an analog audio signal indicating a music. Because each piece of sound quality control information denotes information for adjusting a sound quality of the music and the digital audio signal is recorded with the pieces of sound quality control information as packed data, when a user selects a piece of particular sound quality control information from the pieces of sound quality control information after the packed data is read out, levels of the pieces of audio data of the digital audio signal are adjusted according to the particular sound quality control information, and a sound quality adjusted digital audio signal is obtained.
Accordingly, the user can easily entertain a music adjusted at a desired sound quality.
The first object is also achieved by the provision of an audio signal recording medium, comprising:
a first data area for recording an digital audio signal composed of a plurality of pieces of audio data which are obtained by sampling an analog audio signal of a channel at a high sampling frequency; and
a second data area for recording a plurality of pieces of sound quality control information, which each denote information for adjusting a sound quality of a music indicated by the digital audio signal recorded in the first data area.
In the above configuration, an digital audio signal indicating a music can be recorded with a plurality of pieces of sound quality control information respectively denoting information for adjusting a sound quality of the music. Therefore, in cases where the digital audio signal is read out with the pieces of sound quality control information, a sound quality of the music can be adjusted to a desired sound quality according to one of the pieces of sound quality control information.
The first object is also achieved by the provision of an audio signal reproducing apparatus for reproducing an analog audio signal from packed data composed of a series of audio data, which is obtained by converting the analog audio signal of a channel, and a plurality of pieces of sound quality control information, which each denote information for adjusting a sound quality of a music indicated by the analog audio signal, comprising:
audio signal decoding means for decoding the packed data to reproduce the series of audio data and the pieces of sound quality control information;
operating means for receiving a user""s instruction requesting the selection of a piece of particular sound quality control information from the pieces of sound quality control information reproduced by the audio signal decoding means;
selecting means for selecting the piece of particular sound quality control information according to the user""s instruction received by the operating means;
signal processing means for adjusting levels of the pieces of audio data reproduced by the audio signal decoding means according to the piece of particular sound quality control information selected by the selecting means to produce a series of sound quality adjusted audio data; and
audio data outputting means for outputting the series of sound quality adjusted audio data produced by the signal processing means.
In the above configuration, because a piece of particular sound quality control information is selected by a user in the operating means and the selecting means, a series of sound quality adjusted audio data is produced by adjusting levels of the pieces of audio data according to the piece of particular sound quality control information. Therefore, the user can easily entertain a music adjusted to a desired sound quality.
The second object is achieved by the provision of an audio signal processing and reproducing method, comprising the steps of:
converting an analog audio signal of a channel into a digital audio signal composed of a plurality of pieces of audio data;
shifting original levels of the pieces of audio data of the digital audio signal by a particular differential level to produce a level-shifted digital audio signal composed of a plurality of pieces of level-shifted audio data having shifted levels;
producing level shift control data indicating the particular differential level;
transmitting or recording the level-shifted digital audio signal and the level shift control data; and
returning the shifted levels of the pieces of level-shifted audio data of the level-shifted digital audio signal transmitted or recorded to the original levels according to the level shift control data transmitted or recorded with the level-shifted digital audio signal to reproduce the pieces of audio data of the digital audio signal having the original levels.
The second object is also achieved by the provision of an audio signal processing apparatus, comprising:
analog-digital converting means for converting an analog audio signal of a channel into a plurality of pieces of audio data of a digital audio signal;
level shifting means for shifting original levels of the pieces of audio data of the digital audio signal obtained by the analog-digital converting means by a particular differential level to produce a plurality of pieces of level-shifted audio data of a level-shifted digital audio signal having shifted levels;
level shift control data producing means for producing level shift control data indicating the particular differential level; and
audio signal encoding means for encoding a set of the pieces of level-shifted audio data obtained by the level shifting means and the level shift control data produced by the level shift control data producing means to produce packed data, the packed data being transmitted or recorded.
In the above steps and configuration, because the level shift control data is transmitted or recorded with the level-shifted digital audio signal, even though the original levels of the pieces of audio data of the digital audio signal are shifted to the shifted levels, the shifted levels of the pieces of level-shifted audio data can be automatically returned to the original levels of the pieces of audio data of the digital audio signal.
The second object is also achieved by the provision of an audio signal recording medium, comprising:
a first data area for recording a series of level-shifted audio data having shifted levels which is obtained by converting an analog audio signal of a channel into pieces of audio data and shifting original levels of the pieces of audio data by a particular differential level to the shifted levels; and
a second data area for recording level shift control data indicating the particular differential level.
In the above configuration, the series of level-shifted audio data having the shifted levels and the level shift control data can be recorded as packed data.
The second object is also achieved by the provision of an audio signal reproducing apparatus for reproducing an analog audio signal from packed data composed of a series of level-shifted audio data having shifted levels, which is obtained by converting the analog audio signal of a channel into pieces of audio data and shifting original levels of the pieces of audio data by a particular differential level to the shifted levels, and level shift control data indicating the particular differential level, comprising:
audio signal decoding means for decoding the packed data to reproduce the series of level-shifted audio data and the level shift control data; and
signal processing means for returning the shifted levels of the pieces of level-shifted audio data obtained by the audio signal decoding means to the original levels to reproduce the pieces of audio data according to the level shift control data.
In the above configuration, in cases where packed data composed of a series of level-shifted audio data and level shift control data are recorded in a recording medium such as a digital versatile disk, the packed data is decoded to the series of level-shifted audio data and the level shift control data in the audio signal decoding means. Thereafter, the shifted levels of the pieces of level-shifted audio data are returned to the original levels according to the level shift control data in the signal processing means.
Accordingly, in cases where an analog audio signal of a channel is converted into the packed data in an processing apparatus, because the digital audio signal can be automatically reproduced from the packed data, a user can entertain a music indicated by the analog audio signal.
The third object is achieved by the provision of an audio signal processing and reproducing method, comprising the steps of:
converting a series of analog audio signals, into which a test tone signal is inserted, into a series of digital audio signals including a test tone digital signal obtained by converting the test tone signal;
arranging each of the digital audio signals in an audio pack;
arranging the test tone digital signal in a test tone audio pack to produce a series of audio packs including the test tone audio pack;
dividing the series of audio packs including the test tone audio pack into a plurality of groups of audio packs;
allocating an audio control pack, in which control information is arranged, to each group of audio packs to set the control information and one group of digital audio signals arranged in one group of audio packs as packed data;
adding mute control information indicating the performance of a mute control to the control information of one piece of packed data in cases where the test tone digital signal is included in the piece of packed data;
recording the pieces of packed data;
reading out the pieces of packed data;
decoding the pieces of packed data to reproduce the control information and one group of digital audio signals from each piece of packed data, the mute control information being reproduced from one piece of packed data in which the test tone digital signal is included;
adjusting levels of the digital audio signals reproduced from the pieces of packed data according to the test tone digital signal;
outputting a sound indicated by one group of digital audio signals reproduced from one piece of packed data for each piece of packed data in cases where any mute control information is not included in the control information of the packed data; and
muting a sound of one group of digital audio signals reproduced from one piece of packed data according to the mute control in cases where the mute control information is included in the control information of the packed data.
The third object is also achieved by the provision of an audio signal processing apparatus, comprising:
analog-digital converting means for converting a plurality of analog audio signals, into which a test tone signal is inserted, into a plurality of digital audio signals respectively composed of a plurality of pieces of audio data, the test tone signal being converted into a test tone digital signal;
audio signal processing means for arranging each of the digital audio signals produced by the analog-digital converting means in an audio pack and arranging the test tone digital signal in a test tone audio pack;
audio signal coding means for dividing the audio packs and the test tone audio pack into a plurality of groups of audio packs, allocating an audio control pack, in which control information is arranged, to each group of audio packs to set the control information and one group of digital audio signals as packed data for each group of digital audio signals, adding mute control information indicating the performance of a mute control to the control information of one audio control pack, in cases where the test tone audio pack is included in one group of audio packs, and transmitting pieces of packed data to mute a sound of one group of digital audio signals of one piece of packed data in cases where the mute control information is included in the control information of the series of packed data.
The third object is also achieved by the provision of an audio signal reproducing apparatus for reproducing a series of analog audio signals, into which a test tone signal is inserted, from a series of packed data, which are obtained by converting the series of analog audio signals into a series of digital audio signals, converting the test tone signal into a test tone digital signal, arranging each of the digital audio signals in an audio pack, arranging the test tone digital signal in a test tone audio pack to produce a series of audio packs including the test tone audio pack, dividing the series of audio packs including the test tone audio pack into a plurality of groups of audio packs, allocating an audio control pack, in which control information is arranged, to each group of audio packs to set the control information and one group of digital audio signals arranged in one group of audio packs as packed data, and adding mute control information indicating the performance of a mute control to the control information of one piece of packed data in cases where the test tone digital signal is included in the piece of packed data, comprising:
audio signal decoding means for decoding the pieces of packed data to reproduce the control information and one group of digital audio signals for each piece of packed data, the mute control information being reproduced from one piece of packed data in which the test tone digital signal is included;
signal processing means for adjusting levels of the digital audio signals reproduced from the pieces of packed data by the audio signal decoding means according to the test tone digital signal;
control means for judging for each piece of control information whether or not the mute control information is included in the control information reproduced by the audio signal decoding means and outputting a mute control instruction to perform the mute control for a particular group of digital audio signals of a piece of particular packed data in cases where the mute control information is included in the control information of the piece of particular packed data; and
mute control performing means for performing the mute control to mute an output sound of the particular group of digital audio signals according to the mute control instruction output from the control means and outputting a sound of the groups of digital audio signals other than the particular group of digital audio signals.
In the present invention, a test tone signal set to a known high level is inserted into a series of analog audio signals indicating a music, and levels of the analog audio signals are adjusted according to the test tone signal in an audio signal reproducing operation by setting the known high level of the test tone signal to a prescribed level. In this case, because the test tone signal is set to the high level, an output sound of the test tone signal gives an unpleasant feeling to a listener or a speaker is broken by the output sound. To prevent this drawback, an output sound of the test tone signal is muted while a sound of the analog audio signals indicating a music is output.
In the above steps and configuration, each digital audio signal produced from one analog audio signal is arranged in one audio pack, control information is arranged in an audio control pack, packed data is composed of control information arranged in one audio control pack and a group of digital audio signals arranged in a group of audio packs, and pieces of packed data are recorded.
In this case, a test tone digital signal produced from a test tone signal is arranged in a test tone audio pack, and mute control information is added to the control information of one piece of packed data in cases where the test tone digital signal is included in the piece of packed data.
Thereafter, the pieces of packed data are read out and decoded to reproduce the control information and one group of digital audio signals from each piece of packed data, and levels of the digital audio signals of the pieces of packed data are adjusted according to the test tone digital signal. Also, in cases where the mute control information is included in one piece of control information, a sound indicated by one group of digital audio signals relating to the control information is muted. Therefore, even though a sound indicated by the digital audio signals is output, the test tone signal does not give an unpleasant feeling to a user.
The third object is also achieved by the provision of an audio signal recording medium, comprising:
a plurality of first data areas for respectively recording a series of first packed data obtained by converting a plurality of analog audio signals, into which a test tone signal is inserted, into a plurality of digital audio signals, arranging each of the digital audio signals in an audio pack, dividing the audio packs into a plurality of groups of audio packs, allocating a first audio control pack, in which control information indicating the control of the digital audio signals is arranged, to each group of audio packs to set the control information and one group of digital audio signals as one series of first packed data; and
a second data area for recording a series of second packed data obtained by converting a test tone signal inserted into the plurality of analog audio signals into a test tone digital signal, arranging the test tone digital signal in a test tone audio pack and allocating a second audio control pack, in which control information indicating the control of the digital audio signals and mute control information indicating the performance of a mute control are arranged, to the test tone audio pack and one or more audio packs relating to one or more digital audio signals obtained from one or more analog audio signals adjacent to the test tone signal to set the control information, the mute control information and the digital audio signals as the series of second packed data, a sound of digital audio signals being muted according to the mute control in cases where the series of second packed data is reproduced.
In the above configuration, each series of packed data in which the control information having no mute control information and one group of digital audio signals are packed is recorded in one first data area, and a series of packed data in which the control information having the mute control information and one group of digital audio signals are packed is recorded in the second data area. Therefore, even though a series of analog audio signals into which a test tone signal is inserted is converted into digital audio signals and a test tone digital signal, the digital audio signals can be recorded with the control information having no mute control information, and the test tone digital signal can be recorded with the control information having the mute control information.